Nutrition in Canola

Boron

Constraint – Boron

Plant use

It is mainly involved in the movement of sugars, but also in the metabolism of nitrogen, carbohydrates, and hormones, and in the uptake and efficient use of calcium

Boron may induce both toxicities and deficiencies in Australia

Symptoms

Young plants develop shortened stems and deformed leaves that cup outwards and thicken

The emerging leaf is red-brown to purple, and may have interveinal blotching

The leaf may suffer tip and edge death which slowly kills the whole leaf

The growing point may die

Flowers form but abort

Damage

Deficiencies often disappear after rainfall since plant roots may be unable to access boron in dry soils

Yield penalty is rare, but severe deficiency will cause reduction in seed production

Management

A plant tissue test should be used to confirm boron deficiency. Seek expert advice to determine the appropriate boron types and application rates, and apply a boron fertiliser. Retest in 2-3 years. Be careful to avoid higher rates than necessary as this can cause boron toxicity in plants. Liming also increases soil boron availability.